1. Field of the Invention
The invention relates in general to a copper conducting wire structure and a fabricating method thereof, and more particularly to a copper conducting wire structure having a buffer layer and a fabricating method thereof.
2. Description of the Related Art
Thin film transistor planar display, the thin film transistor liquid crystal display (TFT-LCD) in particular, mainly uses the thin film transistor arranged in matrix and appropriate electronic components such as capacitor and adaptor to drive liquid crystal pixels so that rich colored patterns can be generated. The TFT-LCD having the features of slimness, low power-consumption and low radiation is now widely used in portable electronic products such as notebook and personal digital assistant (PDA). Even the conventional cathode ray tube (CRT) monitor of the desktop computer is now gradually replaced by the liquid crystal monitor.
The conducting wire of the structure of the TFT-LCD is mainly made of aluminum alloy or aluminum composite film. To overcome the RC delay problem generated by large-sized and high resolution TFT-LCD or LCD-TV, the conducting wire is made of material having a high electric conductivity. The most commonly used materials for the conducting wire include copper (Cu) whose electric conductivity is approximately equal to 1.7×10-6 Ω-cm, aluminum (Al) whose electric conductivity is approximately equal to 2.6×10-6 Ω-cm, titanium (Ti) whose electric conductivity is approximately equal to 41.6×10-6 Ω-cm, molybdenum (Mo) whose electric conductivity is approximately equal to 5.7×10-6 Ω-cm, chromium (Cr) whose electric conductivity is approximately equal to 12.8×10-6 Ω-cm, nickel (Ni) whose electric conductivity is approximately equal to 6.8×10-6 Ω-cm. Therefore, using copper whose electric conductivity is higher to replace aluminum or aluminum alloy conducting wire whose electric conductivity is lower has become a hot topic of research in the industry.
Referring to FIG. 1, a cross-sectional view of a conventional copper conducting wire structure is shown. According to conventional fabricating method of copper conducting wire structure, at first, a copper layer is sputtered on a glass substrate 101. Next, the copper layer is etched to form patterned copper layer 103 according to micro-filming manufacturing process. After that, subsequent manufacturing processes would follow. For example, a silicon-oxide layer 105, an amorphous Silicon (a-Si) layer 107 and an n+a-Si layer 109 are sequentially formed on the patterned copper layer 103.
Despite that copper conducting wire structure has a better conductivity, the poor adhesion between copper and glass results in a poor bonding strength between the patterned copper layer and the glass substrate, reducing the electric conductivity of the copper conducting wire structure.